<template>
  <div class="kl-dialog" v-if="dialogVisible">
    <!-- 遮罩 -->
    <div class="kl-mask" :id="klMaskId" v-if="modal" @click="close"></div>
    <!-- 弹窗 -->
    <!-- 这儿需要mousedown来控制顺序 -->
    <div
      :id="klDialogId"
      class="kl-dialog-container resize-container"
      v-dragDialog="{ top: top }"
      :style="{ width: width, top: top }"
      @mousedown="setZIndex"
    >
      <!-- 弹窗头部 -->
      <slot name="header">
        <!-- 必须要有这个kl-dailog-header类才能拖拽 -->
        <div class="kl-dailog-header cc">
          <div class="kl-dailog-header-title">
            {{ title }}
          </div>
          <div class="kl-dailog-header-close" @click="close">
            <i class="el-icon-close kl-dailog-header-close-icon"></i>
          </div>
        </div>
      </slot>

      <!-- 弹窗中间内容 -->
      <slot> default </slot>

      <!-- 弹窗底部 -->
      <slot name="footer">
        <div class="kl-dailog-footer">
          <el-button @click="close">取消</el-button>
          <el-button type="primary" @click="close">确定</el-button>
        </div>
      </slot>
    </div>
  </div>
</template>

<script>
export default {
  name: "klDialog",
  props: {
    // 控制显示隐藏
    dialogVisible: {
      type: Boolean,
      default: false,
    },
    // 是否显示遮罩
    modal: {
      type: Boolean,
      default: true,
    },
    // 头部标题
    title: {
      type: String,
      default: "",
    },
    // 弹窗宽
    width: {
      type: String,
      default: "30%",
    },
    // 距离顶部的距离
    top: {
      type: String,
      default: "20%",
    },
  },
  data() {
    return {
      klMaskId: "",
      klDialogId: "",
    };
  },
  created() {
    this.init();
  },

  directives: {
    dragDialog: {
      /*eslint-disable*/
      inserted: function (el, { value, minWidth = 400, minHeight = 200 }) {
        // 让弹窗居中
        const dialogHeight = el.clientHeight ?? 0;
        const dialogWidth = el.clientWidth ?? 0;

        // 获取可视区域的宽高
        const windowWidth = document.documentElement.clientWidth ?? 0;
        const windowHeight = document.documentElement.clientHeight ?? 0;

        // 弹窗的可移动范围
        const leftMax = windowWidth - dialogWidth;
        const topMax = windowHeight - dialogHeight;

        //还需要判断是否传入了top,left值
        const { top, center } = value;

        const left = (windowWidth - dialogWidth) / 2;

        if (!center) {
          // 没有设置center
          if (top.includes("%") || top.includes("px")) {
            el.style.top = top;
          } else {
            el.style.top = top + "px";
          }

          el.style.left = left + "px";
        } else {
          el.style.top = (windowHeight - dialogHeight) / 2 + "px";
          el.style.left = (windowWidth - dialogWidth) / 2 + "px";
        }

        const el_header = el.querySelector(".kl-dailog-header");
        // 只有点击头部才能拖拽
        if (!el_header) return;
        let headerHeight = el_header.clientHeight - 0;
        // 缩放相关
        el.onmousemove = function (e) {
          // 判断当前鼠标是否处于可以拖拽的边缘，不包含头部
          if (
            e.clientX > el.offsetLeft + el.clientWidth - 10 ||
            el.offsetLeft + 10 > e.clientX
          ) {
            el.style.cursor = "w-resize";
          } else if (
            el.scrollTop + e.clientY >
            el.offsetTop + el.clientHeight - 10 - headerHeight
          ) {
            el.style.cursor = "s-resize";
          } else {
            el.style.cursor = "default";
          }

          el.onmousedown = (e) => {
            // 获取头部的宽高以及到可视区域的距离
            const el_header_rect = el_header.getBoundingClientRect();

            if (!el_header_rect) return;
            let offsetTopHeader = el_header_rect.top - 0;

            // 判断当前元素是否是可拖拽的头部元素
            if (headerHeight > e.pageY - offsetTopHeader) {
              // 是头部，拖拽相关
              // 获取到鼠标与被拖拽节点的相对位置
              let disx = e.pageX - el.offsetLeft;
              let disy = e.pageY - el.offsetTop;

              // 获取弹窗的宽高
              let width = el.clientWidth ?? 0;
              let height = el.clientHeight ?? 0;

              // 设置其他弹窗的z-index 100
              let maxZIndex = 100;
              document
                .querySelectorAll(".kl-dialog-container")
                .forEach((item) => {
                  let zIndex = item.style.zIndex;
                  zIndex = zIndex ? zIndex - 0 : 100;
                  if (zIndex > maxZIndex) {
                    maxZIndex = zIndex;
                  }
                });
              el.style.zIndex = maxZIndex + 1;

              document.onmousemove = function (e) {
                const el_rect = el.getBoundingClientRect();

                if (!el_rect) return;

                // 获取弹窗到可视区域的距离
                let offsetTopEl = el_rect.top - 0;
                let offsetLeftEl = el_rect.left - 0;

                let left = e.pageX - disx;
                let top = e.pageY - disy;

                // 对弹窗的位置进行限制
                if (offsetTopEl < 0 || top < 0) {
                  top = 0;
                }

                if (offsetLeftEl < 0 || left < 0) {
                  left = 0;
                }

                if (offsetTopEl + height > windowHeight || top > topMax) {
                  top = windowHeight - height;
                }

                if (offsetLeftEl + width > windowWidth || left > leftMax) {
                  left = windowWidth - width;
                }

                // 重新设置被拖拽节点的位置
                el.style.left = left + "px";
                el.style.top = top + "px";
              };
              document.onmouseup = function () {
                document.onmousemove = document.onmouseup = null;
              };
            } else {
              const clientX = e.clientX; // 鼠标点击时的X坐标
              const clientY = e.clientY; // 鼠标点击时的Y坐标
              let elW = el.clientWidth; // 当前元素的宽度
              let elH = el.clientHeight; // 当前元素的高度
              let EloffsetLeft = el.offsetLeft; // 元素距离左边的距离
              let EloffsetTop = el.offsetTop; // 元素距离顶部的距离
              el.style.userSelect = "none";
              let ELscrollTop = el.scrollTop; // 元素滚动条距离顶部的距离
              // 不是头部，缩放相关
              document.onmousemove = function (e) {
                e.preventDefault(); // 移动时禁用默认事件
                //左侧鼠标拖拽位置
                if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {
                  //往左拖拽
                  if (clientX > e.clientX) {
                    el.style.width = elW + (clientX - e.clientX) * 2 + "px";
                    el.style.left = EloffsetLeft - (clientX - e.clientX) + "px";
                  }
                  //往右拖拽
                  if (clientX < e.clientX) {
                    if (el.clientWidth < minWidth) {
                    } else {
                      el.style.width = elW - (e.clientX - clientX) * 2 + "px";
                      el.style.left =
                        EloffsetLeft + (e.clientX - clientX) + "px";
                    }
                  }
                }

                //右侧鼠标拖拽位置
                if (
                  clientX > EloffsetLeft + elW - 10 &&
                  clientX < EloffsetLeft + elW
                ) {
                  //往左拖拽
                  if (clientX > e.clientX) {
                    if (el.clientWidth < minWidth) {
                    } else {
                      el.style.width = elW - (clientX - e.clientX) * 2 + "px";
                      el.style.left =
                        EloffsetLeft + (clientX - e.clientX) + "px";
                    }
                  }

                  //往右拖拽
                  if (clientX < e.clientX) {
                    el.style.width = elW + (e.clientX - clientX) * 2 + "px";
                    el.style.left = EloffsetLeft + (clientX - e.clientX) + "px";
                  }
                }
                //底部鼠标拖拽位置
                if (
                  ELscrollTop + clientY > EloffsetTop + elH - 20 &&
                  ELscrollTop + clientY < EloffsetTop + elH
                ) {
                  //往上拖拽
                  if (clientY > e.clientY) {
                    if (el.clientHeight < minHeight) {
                    } else {
                      el.style.height = elH - (clientY - e.clientY) * 2 + "px";
                      el.style.top = EloffsetTop + (clientY - e.clientY) + "px";
                    }
                  }
                  //往下拖拽
                  if (clientY < e.clientY) {
                    el.style.height = elH + (e.clientY - clientY) * 2 + "px";
                    el.style.top = EloffsetTop + (clientY - e.clientY) + "px";
                  }
                }
              };
              //拉伸结束
              document.onmouseup = function (e) {
                document.onmousemove = null;
                document.onmouseup = null;
              };
            }
          };
        };
      },
      /*eslint-disable*/
    },
  },

  watch: {
    dialogVisible(val) {
      if (val) {
        this.setZIndex();
      }
    },
  },

  methods: {
    createId() {
      return Date.now() + Math.random().toString(36).substr(2);
    },
    // 关闭弹窗
    close() {
      this.$emit("close");
    },

    // 给每个弹窗添加一个id
    initId() {
      this.klMaskId = this.createId();
      this.klDialogId = this.createId();
    },

    // 将当前弹窗的z-index设置为最高
    async setZIndex() {
      const { klDialogId } = this;
      await this.$nextTick();
      const els = document.querySelectorAll(".kl-dialog-container");

      let maxZIndex = 100;
      els.forEach((item) => {
        let zIndex = item.style.zIndex;
        zIndex = zIndex ? zIndex - 0 : 100;
        if (zIndex > maxZIndex) {
          maxZIndex = zIndex;
        }
      });

      const el = document.querySelector("#" + klDialogId);
      if (el) {
        el.style.zIndex = maxZIndex + 1;
      }
    },

    // 初始化
    init() {
      this.initId();
      // 设置当前的弹窗层级最高
      this.setZIndex();
    },
  },
};
</script>

<style lang="scss" scoped>
.kl-mask {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vw;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 100;
}
.kl-dialog-container {
  position: fixed;
  background: #fff;
  border-radius: 2px;
  box-shadow: 0 1px 3px rgb(0 0 0 / 30%);
  box-sizing: border-box;
  background-color: #fff;
  z-index: 100;
}

.kl-dailog-header {
  padding: 0 20px;
  height: 54px;
  line-height: 54px;
  position: relative;
  font-size: 18px;
  font-weight: 500;
  user-select: none;
}
.kl-dailog-header-close {
  position: absolute;
  top: 50%;
  right: 20px;
  transform: translateY(-50%);
  cursor: pointer;
}
.kl-dailog-header-close-icon {
  color: #aaa;
}
.kl-dailog-footer {
  padding: 0 20px;
  height: 70px;
  line-height: 70px;
  text-align: right;
}

.cc {
  cursor: move;
}
</style>
